Get filename without Content-Disposition

Question

I am looking for a solution for this problem for days and I can't find any.

I want to download a file from a webserver with a webclient. The download works fine, but I can't get the real filename, which is very important for me.

I read on many homepages, that the filename should be saved in the Content-Disposition-Header. Unfortunately this header of the site is empty. I tried to get it with:

string header_contentDisposition ="";
using (WebClient client = new WebClient())
            {
                client.OpenRead(link);

                header_contentDisposition = client.ResponseHeaders["Content-Disposition"];
                MessageBox.Show(header_contentDisposition);
            }

There is no information saved inside this header.

If I try to download the file with my Browser (IE, Opera, Chrome) the filename gets shown in the filedialog, so it has to be saved somewhere.

Can you imagine where I can find it?

EDIT: I can't extract it from the URL, because the link is generated by php like

http://www.example.com/download.php?id=10

Can you dump the headers which *are* present? Or perhaps browsers are defaulting it from the URL? — Jon Skeet, Nov 26 '12 at 18:24
All headers I got: Age = 292161 Connection=keep-alive Accept-Ranges=bytes Content-Length=15953830 Cache-Control=max-age=31536000 Content-Type=application/vnd.android.package-archive Date=Fri, 23 Nov 2012 09:21:40 GMT Expires=Sat, 23 Nov 2013 09:21:40 GMT Last-Modified=Fri, 23 Nov 2012 08:38:35 GMT Server=nginx — user1854270, Nov 26 '12 at 18:35
for example: http://upload.p-kratzer.com/index.php?dir=&file=GE.JPG of course, in this particular case i could get the filename from the "file" parameter, but I have to download from different servers and often that's not possible — user1854270, Nov 26 '12 at 18:40
Rather than giving an example which *isn't* representative of the problem, why don't you give us one which *is*? i.e. a URL where: 1) The filename isn't in the URL; 2) The filename isn't in the Content-Dispoition; 3) Browsers still manage to download the file correctly. — Jon Skeet, Nov 26 '12 at 18:41
here it is:http://upload.p-kratzer.com/index.php?dir=&file=asdfasdfwervdcvvedb (the real file name should be "wetter.JPG") — user1854270, Nov 26 '12 at 18:52
What I would do is use the debugger, and see what the content of your response is, and see if anything that looks like a filename is in there — Sam I am says Reinstate Monica, Nov 26 '12 at 19:01

Lunyx · Accepted Answer · 2012-11-26T19:32:38.580

You can try this:

        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        try
        {

            HttpWebResponse res = (HttpWebResponse)request.GetResponse();
            using (Stream rstream = res.GetResponseStream())
            {
                string fileName = res.Headers["Content-Disposition"] != null ?
                    res.Headers["Content-Disposition"].Replace("attachment; filename=", "").Replace("\"", "") :
                    res.Headers["Location"] != null ? Path.GetFileName(res.Headers["Location"]) : 
                    Path.GetFileName(url).Contains('?') || Path.GetFileName(url).Contains('=') ?
                    Path.GetFileName(res.ResponseUri.ToString()) : defaultFileName;
            }
            res.Close();
        }
        catch { }

Tested this on http://upload.p-kratzer.com/index.php?dir=&file=asdfasdfwervdcvvedb and it does return wetter.JPG.

Great Lunyx. Thank you. But when i use this for google drive links get a big result string. For example "attachment;filename=filename.apk;filename*=UTF-8''filename.apk" — smedasn, Mar 09 '18 at 11:24
@smedasn Probably the space between `attachment;` and `filename=` is missing in the header Google drive supplies. It's not required by the standard, so you should handle that case. — Tom Lint, Aug 07 '18 at 12:15

Get filename without Content-Disposition

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